An estimated 50 million people in the United States have high blood pressure (systolic blood pressure [SBP] =/> 140mmHg and/or diastolic BP [DBP] =/> 90mmHg), or are taking antihypertensive medications. All factors considered and remaining constact, the incremental cost of treating 25 million patients with a drug costing $100/patient-year of therapy compared to one costing $500/patient-year of therapy is $10 billion. Hypertension is considerably more common among African Americans than Caucasians, and its sequelae are also more frequent among African Americans. Thus, the Antihypertensive and Lipid-lowering to Prevent Heart Attack Trial (ALLHAT), a nation-wide, practice-based, randomized, clinical trial of antihypertensive pharmacological treatments and cholesterol-lowering to prevent heart attack in a specific subset of 40,000 high-risk hypertensive patients, is to include at least 55% African Americans. The purpose of the antihypertensive treatment arm is to determine if the combined incidence of fatal coronary heart disease and non-fatal myocardial infarction between diuretic treatment and three alternative (and more expensive) hypertensive pharmacological treatments. The purpose of the lipid-lowering treatment arm is to determine if lowering serum cholesterol in moderately hypercholesterolemic men and women aged 60 years and older with a specific 3-hydroxymethylglutaryl co- enzyme A reductase inhibitor, will reduce all-cause mortality as compared to a control group receiving "usual care." Secondary objectives of both trial components are to compare the effects of their respective treatment regimens on cardiovascular mortality, major morbidity, health costs, and health-related quality of life.